Patient's question:
I am 36 years old and currently 19 weeks pregnant (less than 20 weeks). The doctor said it is not necessary for me to have the maternal serum screening, and I should directly undergo amniocentesis. Please ask if it is still necessary for me to have the maternal serum screening.Thank you!
Doctor's answer:
The Down syndrome screening is a test to screen for the possibility of a fetus having Down syndrome. The results are not a definitive diagnosis but rather a risk factor, indicating the likelihood of having Down syndrome. Further testing (such as amniocentesis) is necessary for confirmation. Therefore, there is no need to panic until the results of further testing are available.Through screening, if the risk value is high, it is advisable to undergo amniocentesis earlier to examine the fetus's chromosomes, which can help determine if there is a 21-trisomy. Later, ultrasound can be used to assess the fetal eye distance, ear position, and neck skin thickness to identify any potential 21-trisomy. Additionally, umbilical blood flow testing can be used for further evaluation. However, the final diagnosis is based on chromosomal karyotyping.
All expectant mothers should undergo this test between weeks 14 and 20 of pregnancy. A negative report only indicates a low chance of the fetus having this congenital abnormality but does not completely rule it out.
Prenatal screening results are expressed as risk rates. A result of >1/275 is considered screening positive, requiring further amniocentesis.